diff --git a/include/stdio.h b/include/stdio.h
index 5a5b82bc665e..f55aaf7c7274 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -144,6 +144,7 @@ struct __sFILE {
 	int	_fl_count;	/* recursive lock count */
 	int	_orientation;	/* orientation for fwide() */
 	__mbstate_t _mbstate;	/* multibyte conversion state */
+	int	_flags2;	/* additional flags */
 };
 #ifndef _STDFILE_DECLARED
 #define _STDFILE_DECLARED
@@ -176,6 +177,8 @@ __END_DECLS
 #define	__SALC	0x4000		/* allocate string space dynamically */
 #define	__SIGN	0x8000		/* ignore this file in _fwalk */
 
+#define	__S2OAP	0x0001		/* O_APPEND mode is set */
+
 /*
  * The following three definitions are for ANSI C, which took them
  * from System V, which brilliantly took internal interface macros and
diff --git a/lib/libc/stdio/fdopen.c b/lib/libc/stdio/fdopen.c
index 8bd9c2ddbe01..fbe37e881428 100644
--- a/lib/libc/stdio/fdopen.c
+++ b/lib/libc/stdio/fdopen.c
@@ -91,9 +91,8 @@ fdopen(int fd, const char *mode)
 	 * O_APPEND bit set, assert __SAPP so that __swrite() caller
 	 * will _sseek() to the end before write.
 	 */
-	/* XXX: Reuse __SALC for O_APPEND. */
 	if (fdflags & O_APPEND)
-		fp->_flags |= __SALC;
+		fp->_flags2 |= __S2OAP;
 	else if (oflags & O_APPEND)
 		fp->_flags |= __SAPP;
 	fp->_file = fd;
diff --git a/lib/libc/stdio/findfp.c b/lib/libc/stdio/findfp.c
index 0eabe82d753f..b8bb5afb551c 100644
--- a/lib/libc/stdio/findfp.c
+++ b/lib/libc/stdio/findfp.c
@@ -155,6 +155,7 @@ __sfp(void)
 /*	fp->_fl_mutex = NULL; */ /* once set always set (reused) */
 	fp->_orientation = 0;
 	memset(&fp->_mbstate, 0, sizeof(mbstate_t));
+	fp->_flags2 = 0;
 	return (fp);
 }
 
diff --git a/lib/libc/stdio/fopen.c b/lib/libc/stdio/fopen.c
index b26f63734d99..9ab61ba157a4 100644
--- a/lib/libc/stdio/fopen.c
+++ b/lib/libc/stdio/fopen.c
@@ -92,8 +92,7 @@ fopen(const char * __restrict file, const char * __restrict mode)
 	 * fseek and ftell.)
 	 */
 	if (oflags & O_APPEND) {
-		/* XXX: Reuse __SALC for O_APPEND. */
-		fp->_flags |= __SALC;
+		fp->_flags2 |= __S2OAP;
 		(void)_sseek(fp, (fpos_t)0, SEEK_END);
 	}
 	return (fp);
diff --git a/lib/libc/stdio/freopen.c b/lib/libc/stdio/freopen.c
index 8b68bacc3f6a..e0104c88eef6 100644
--- a/lib/libc/stdio/freopen.c
+++ b/lib/libc/stdio/freopen.c
@@ -187,6 +187,7 @@ freopen(const char * __restrict file, const char * __restrict mode,
 	fp->_lb._size = 0;
 	fp->_orientation = 0;
 	memset(&fp->_mbstate, 0, sizeof(mbstate_t));
+	fp->_flags2 = 0;
 
 	if (f < 0) {			/* did not get it after all */
 		if (isopen)
@@ -241,8 +242,7 @@ freopen(const char * __restrict file, const char * __restrict mode,
 	 * fseek and ftell.)
 	 */
 	if (oflags & O_APPEND) {
-		/* XXX: Reuse __SALC for O_APPEND. */
-		fp->_flags |= __SALC;
+		fp->_flags2 |= __S2OAP;
 		(void) _sseek(fp, (fpos_t)0, SEEK_END);
 	}
 	FUNLOCKFILE(fp);
diff --git a/lib/libc/stdio/ftell.c b/lib/libc/stdio/ftell.c
index 0d2222b6958f..abb6da11966c 100644
--- a/lib/libc/stdio/ftell.c
+++ b/lib/libc/stdio/ftell.c
@@ -119,8 +119,7 @@ _ftello(FILE *fp, fpos_t *offset)
 		if (HASUB(fp))
 			pos -= fp->_r;  /* Can be negative at this point. */
 	} else if ((fp->_flags & __SWR) && fp->_p != NULL) {
-		/* XXX: Reuse __SALC for O_APPEND. */
-		if (fp->_flags & (__SAPP|__SALC)) {
+		if ((fp->_flags & __SAPP) || (fp->_flags2 & __S2OAP)) {
 			int serrno = errno;
 
 			errno = 0;
diff --git a/lib/libc/stdio/stdio.c b/lib/libc/stdio/stdio.c
index fc2e74b356b9..5d6fb9ac5644 100644
--- a/lib/libc/stdio/stdio.c
+++ b/lib/libc/stdio/stdio.c
@@ -117,8 +117,7 @@ _swrite(FILE *fp, char const *buf, int n)
 	ret = (*fp->_write)(fp->_cookie, buf, n);
 	/* __SOFF removed even on success in case O_APPEND mode is set. */
 	if (ret >= 0) {
-		/* XXX: Reuse __SALC for O_APPEND. */
-		if ((fp->_flags & __SOFF) && !(fp->_flags & __SALC) &&
+		if ((fp->_flags & __SOFF) && !(fp->_flags2 & __S2OAP) &&
 		    fp->_offset <= OFF_MAX - ret)
 			fp->_offset += ret;
 		else